Betting on sports is a popular pastime, and with good reason: The outcome of a sporting event is often highly unpredictable, leaving room for speculation and, more importantly, betting action! However, if you’re looking to place a wager on a sporting event and don’t know how to calculate the odds, this can leave you at a disadvantage. To put it simply, the odds determine the probability of something (in this case, a sporting event) happening, and it’s absolutely essential that you understand how to calculate them so that you can make the right wagers and enjoy your sports betting experience without any risks.

## The Minus System

The Minus (M) system is one of the most popular ways of calculating the odds in sports betting, and it can be applied to basketball, baseball, and hockey. It’s named after the founding father of modern sports odds theory, Dr. Edwin H. Minus. Unlike most other systems, the Minus System doesn’t rely on arbitrary or controversial measures such as points scored, or the strength of a team, to generate its odds; instead, it works with readily available and verifiable information, such as the number of games played between two teams and the number of overtimes in a game.

Let’s take a closer look at how it works.

### How To Calculate The Odds In The Minus System

As mentioned, the Minus System doesn’t utilize any subjective or ambiguous measures to establish the odds for a particular sporting event. In fact, it doesn’t use any measures at all! The only two things that it relies on are: (1) the number of games played between two teams and (2) the number of overtimes in a game. To calculate the odds in the Minus System, you perform a simple subtraction:

- For every additional overtime period, take away 1 from the number of games won
- For every additional game won, take away 1 from the number of overtime periods

So, if you have two teams, Team A and Team B, playing each other (based on whatever criteria you choose, such as winning percentage or point spread), then the odds for Team A winning are simply:

- Odds of 1.0 (even chance) if there are no overtime periods
- Odds of 1.5 (1 in 2) if there is 1 overtime period
- Odds of 2.0 (2 in 2) if there are 2 overtime periods
- Odds of 2.5 (1 in 4) if there are 3 overtime periods
- Odds of 3.0 (1 in 8) if there are 4 overtime periods
- And so on…
- Odds of 5.0 (1 in 32) for a game that goes into 7 overtimes

Keep in mind: The oddsmaker’s line is often highly subjective and, as aforementioned, ambiguous; however, using the Minus System, you are bound to get some indication of how particular teams and players are likely to do in future games. In other words, a team that hasn’t won a game yet is almost certainly going to lose against every other team they play against. This tendency to over- or under-estimate the performance of a given team makes using the Minus System a must for truely experienced sports bettors.

### How To Apply The Minus System In Practice

As alluded to, the Minus System is essentially an odds-calculating algorithm, which means it’s fairly easy to implement in practice. For instance, if you have a betting friend who’s willing to share their sports book with you, all you have to do is input the numbers from the previous section into the algorithm and the odds will be generated for you. Additionally, if you’re using a sports book that offers in-play betting, then the odds for the current game will already be available for you to wager on!

Now, it is essential that you keep in mind one important thing about the Minus System: Its output is inherently subjective and, therefore, open to interpretation. It’s very unlikely that you will ever get exact odds from the algorithm, especially if you’re applying it to a game with a large number of overtimes. To illustrate, if you’re using a set of regular-season NFL games as the basis for your bet, then the odds for the first game to go into 7 overtimes will be 1 in 32, while the first game to go into 6 overtimes will have odds of 1 in 64. This is simply because there are an infinite number of permutations for what could happen in an NFL game that goes into the multiple overtimes, while there are only 2 possible outcomes for every other game.

## The Plus System

The Plus (P) system is another popular way of calculating the odds in sports betting, and it can be applied to most kinds of sporting events, including football, basketball, and baseball. Like the Minus System, the Plus System doesn’t utilize any subjective or ambiguous measures to establish the odds for a particular sporting event; instead, it relies on the accumulation of point-spread or win-total (W) data over a set number of games to generate its odds. Therefore, in theory, if you applied it to a game with a large number of overtimes, then the odds for the game to end in a tie would be 1 in 1,000, meaning there’s a 1 in 1,000 chance of it ending in a tie!

Let’s take a closer look at how it works.

### How To Calculate The Odds In The Plus System

The Plus System is, in theory, an objective and unambiguous system for calculating the odds of a given sporting event; however, like the Minus System, it is highly likely that you will not end up with the exact odds that it generates, especially if you’re applying it to a game with a large number of overtimes. To put it simply, the Plus System is, in effect, a point-scoring system that accumulates data over a set number of games (usually 5) and converts this data into an indication of how the final result of a game will unfold. To generate the oddss in the Plus System, you simply add up the points scored (or, in the case of baseball, the runs allowed) by the contestants (teams) involved in the game. So, if you have two teams, Team A and Team B, playing each other (based on whatever criteria you choose, such as winning percentage or point spread), then the odds for Team A winning are simply:

- Odds of 1.0 (even chance) if the number of points is 0 or 24
- Odds of 1.5 (1 in 2) if there are 3 points
- Odds of 2.0 (2 in 2) if there are 4 points
- Odds of 2.5 (1 in 4) if there are 5 points
- Odds of 3.0 (1 in 8) if there are 6 points
- And so on…
- Odds of 5.0 (1 in 32) for a game in which the total points are 31 or more

Keep in mind: The point-scoring systems in use today were originally designed for use in horse racing back in the 1800s, and they haven’t really evolved much since then! However, over the years, they’ve gained a lot of popularity in the sports betting world and are considered to be among the most reliable tools available to sports bettors today.

### How To Apply The Plus System In Practice

Like the Minus and the Plus Systems, the Plus System is also an algorithm that can be applied to practical use. If you have a betting friend willing to share their sports book with you, then all you have to do is input the numbers from the previous section into the algorithm and the odds will be generated for you. Additionally, if you’re using a sports book with in-play betting, then the plus system will already be activated and the current line (the amount of money wagered on each outcome) will be displayed for you.

As with the Minus and the Plus Systems, keep in mind that the output of the Plus System is subject to interpretation, especially if you’re applying it to a game with a large number of overtimes. For example, if you’re using a set of regular-season NFL games as the basis of your bet, then the odds for the first game to go into 7 overtimes will be 1 in 1,000, while the first game to go into 6 overtimes will have odds of 1 in 5,000!